The invention is in the field of control systems. More particularly, the invention is an electrically-controlled hydraulic system designed to enable the remote control of a device. In the preferred manner of use, the system employs a hydraulic actuator to control an undersea-located valve.
It can sometimes be difficult to actuate or control a device, such as a hydraulic actuator for a valve, when the device is located in an area that is not readily accessible. In such cases, one must either employ a system for remotely-actuating/controlling the device, or one must gain access to the device and then operate it manually. Both of these methods can be costly. When manual operation is required, there can also be significant time delays, hazards, or external environmental conditions that limit access.
The above-described problems are commonplace when working with undersea-located devices. For example, undersea oil production control systems employ a number of valves in piping located on, or proximate, the sea floor. Since many of these valves are only actuated occasionally and/or are located where typical methods of remote control are unsatisfactory, operation of the valves is usually achieved manually by a diver or by a Remote-Operated-Vehicle (ROV). It should be noted that the problems associated with manual operation of an undersea-located device are exacerbated when the device is located at any significant depth below the water""s surface.
There have been a number of systems devised to enable remote actuation of an undersea-located device. One such system is taught by Silcox in U.S. Pat. No. 4,095,421. In the Silcox patent, a surface-located acoustic transmitter is employed to send signals to a receiver located proximate an undersea-located rotary valve. Upon actuation, the receiver enables a negative-energy power supply to cause the operation of the rotary valve via a multi-valved actuator. This system has a number of limitations that arise due to the power supply and the arrangement of the valves.
Another example of a system for remotely operating an undersea-located device is taught by Carman et al in U.S. Pat. No. 4,805,657. The patent teaches a valve that includes a receiver and a spring-biased mechanism that can be triggered by an explosive bolt. Once the valve is installed in an undersea location, an operator can transmit an acoustic signal to the valve that will cause the detonation of the explosive bolt. Upon detonation, the spring-biased mechanism causes the valve to change from an open to closed, or closed to open position. Since this system only allows a single actuation of the valve, there is no practical method for testing the actuation system after the valve has been installed.
The invention is a system for remotely-actuating/controlling a device, such as a hydraulic valve actuator. In the preferred manner of deployment, the system is employed on an undersea-located device.
The system includes a pressurized fluid reservoir that can be recharged from one or more gas bottles. A fluid line extends between the reservoir and a main control valve. A pressure-regulating valve is preferably employed in said fluid line to maintain a constant pressure in the fluid going to the main control valve.
The main control valve functions to direct pressurized fluid from the reservoir to a hydraulically-powered device, such as a hydraulic actuator or a hydraulic motor. The control valve is preferably a spool valve and is operated through the action of a hydraulic pilot system.
The hydraulic pilot system preferably employs a xe2x80x9cChristmas treexe2x80x9d/network of xe2x80x9cone-shotxe2x80x9d units. Each one-shot unit is preferably in the form of a squib-actuated valve and a piston accumulator. The pilot system functions by selectively enabling pressurized fluid to exert force on, and move, the control valve""s spool. At the same time, the pilot system provides a flow path out of the control valve for fluid displaced by the spool""s movement.
In the preferred embodiment, the squib-actuated valves of the hydraulic pilot system, and similar valves in the system for pressurizing the reservoir, are initially in a closed position. They can only be opened through the detonation of their squibs. An electrically-powered control system is used for this function.
The control system includes a receiver, controller and preferably a battery unit. In the preferred embodiment, all three of these devices are located proximate the controlled device.
The receiver functions to detect predetermined coded signals sent from a remotely-located transmitter. When the system is used to control an undersea-located device, an acoustic signal is preferred for transmitting a command from the transmitter to the receiver. To accomplish this, the sending unit of the transmitter is located in the water at a distance from the receiver. When the system is employed to control a device that is not near any surface-located structure, the sender unit of the transmitter can be suspended from a ship or lowered into the water from a helicopter. In operation, when the receiver detects a coded signal, it relays the signal to the controller.
The controller preferably includes a logic circuit that analyzes the signals received by the receiver. The controller then accomplishes the requested action by directing a detonating electric signal to certain of the squibs of the squib-actuated valves. This may result in a recharging of the reservoir and/or a functioning of the hydraulic pilot system to affect the control valve.
The above-described system enables remote operation of an actuator, valve or fluid motor in an improved manner compared to the prior art. The system is highly reliable, compact, easily serviceable and relatively low in cost. In the preferred design of the system, there are sufficient xe2x80x9cone-shotxe2x80x9d units to enable multiple cycling of the controlled device. As a result, the system has an extended service life and the system""s reliability and functionality can be tested.